1. Field of the Invention
The present invention relates to a technical field of a print system for outputting a print (photograph) on which an image photographed on a film is reproduced, and in particular, to an image retrieval method allowing an image on a print made on the occasion of film processing and that on a reprint to suitably match each other in such a print system.
2. Description of the Related Art
Up to now, so-called direct exposure for projecting an image on a film onto a photosensitive material (photographic paper) and then performing exposure on the photosensitive material has been a main technique in printing of an image photographed on a photographic film (hereinafter, referred to simply as a film) such as a negative film or a reversal film onto a photosensitive material.
On the other hand, a printer utilizing digital exposure, that is, a digital photographic printer has recently been put into practical use. In the digital photographic printer, an image recorded on a film is photoelectrically read. The read image is converted to a digital signal, which is then subjected to various image processing operations so as to obtain image data for recording. A photosensitive material is subjected to scanning exposure with recording light which has been modulated in accordance with the obtained image data so as to record an image (latent image), thereby obtaining a (finished) print.
The digital photographic printer basically includes: a scanner (image reader) for making reading light incident on a film and reading its projected light so as to photoelectrically read an image recorded on the film; an image processor for performing predetermined processing on image data read by the scanner or image data supplied from a digital camera or the like so as to obtain image data for image recording, that is, an exposure condition; a printer (image recorder) for performing scanning exposure on a photosensitive material, for example, by light beam scanning in accordance with the image data output from the image processor so as to record a latent image; and a processor (developing unit) for performing development processing on the photosensitive material exposed by the printer so as to obtain a (finished) print on which the image is reproduced.
In such a digital photographic printer, images can be processed as digital image data to adjust images, so various operations including the correction of washed-out highlights and flat (dull) shadows due to the taking of pictures with rear light or an electronic flash, sharpening, and the like can be performed in an effective manner to produce prints of the high quality that has been unattainable by the conventional direct exposure.
Moreover, according to the digital photographic printer, even an image photographed by a digital camera or the like can be output as a print.
Not only in such a digital photographic printer but also an analog photographic printer utilizing direct exposure, for a print output from an image photographed on a film, so-called reprinting for reoutputting an image (frame) which has already been printed once as a print is often performed in accordance with the request of a reprint and the like.
In this case, unless a modification is otherwise indicated, it is required that the image reproduced on a previously output print (normally, a print made on the occasion of film processing for reproducing and outputting an image photographed on a photographic film) and the image on a reprint match each other.
However, due to differences in decisions or operations by operators, the previous print and the reprint have often different image colors and densities, leading to many customer complaints.
In order to cope with this problem, for example, a print system allowing a reorder to be placed without dealing with a film has been proposed in JP 09-55834 A or JP 09-179211 A.
In addition, a printing system for efficiently performing the retrieval of image processing information is disclosed in, for example, JP 2000-222437 A and JP 2001-7965 A. Furthermore, an image retrieval device is disclosed in JP 2001-52175 in which a plurality of characteristic amounts are extracted to produce a characteristic vector which is used to retrieve an image similar to the target image from the reference image database where data of plural reference images is stored.
In these prior art documents, image processing is performed during reprinting under the same image processing conditions as those of the printing with film processing so as to obtain the identical image in the reprint and the print made on the occasion of film processing. For this purpose, the image processing conditions of the printing with film processing are recorded in a database along with its image data, so that the database is retrieved during the reprinting so as to fetch out the image processing conditions of the printing with film processing.
However, the conventional image retrieval method has disadvantages in low retrieval performance, retrieval errors due to frame detection errors (positional shift of a frame), and degradation of retrieval efficiency due to a difference in retrieval conditions between printing with film processing and reprinting.